Thermal inkjet technology is widely used for precisely and rapidly dispensing small quantities of fluid. Thermal inkjets eject droplets of fluid out of a nozzle by passing an electrical current through a heating element. The heating element generates heat which vaporizes a small portion of the fluid within a firing chamber. The vapor rapidly expands, forcing a small droplet out of the firing chamber nozzle. The electrical current is then turned off and heating element cools. The vapor bubble rapidly collapses, drawing more fluid into the firing chamber from a reservoir. During printing, this ejection process can repeat thousands of times per second. It is desirable that the heating element be mechanically robust and energy efficient in ejecting droplets.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.